Agriculture Reference
In-Depth Information
problem. Mulching can be an alternative, but it is normally expensive to spread
out in the orchard. Straw, hay, dried grass, wood shavings or any cheap and
easily obtained organic material can be used (Fig. 3.7a). Care has to be taken
to not let the mulch come in close contact with the trunks to avoid excess
moisture and collar rot occurring. Mulch will prevent weeds from growing and
at the same time will allow roots to grow near the surface, where the soil is of
better quality. One problem with mulch if allowed to dry out is a possible risk
of fi res and it can harbour rodent pests. Plastic mulches can be used, especially
in short-lived crops like papaya or pineapple, and their use will be determined
by the economic convenience (Fig. 3.7b). Normally only the plant rows are
mulched, and sometimes just a piece of black polyethylene about 1 m square is
placed around the tree pole to avoid the initial direct weed competition.
No vegetation on the orchard fl oor fi ts better in orchards located in arid
zones like the Peruvian coast or the Florida coralline sands. In desert areas,
there is very little to do to control weeds if drip irrigation is used. In Florida,
herbicides are used after rains to control weeds (see next section). The no-
vegetation approach means no competition with the crop for water or nutrients.
It also allows easier incorporation of manure or cover crops into the soil.
WEED CONTROL
Weeds, as well as associated crops, compete with the fruit trees for water and
nutrients, and in certain circumstances can be an important factor in lowering
(a)
(b)
Fig. 3.7.
Weed control can be achieved by placing organic mulch under the
trees (a), or plastic mulch (b) is also used on shorter-cycle crops or during tree
establishment.
